1. Field of the Invention
The present invention relates to a method for producing a screened layer for an electrophotographic element by applying a homogeneous layer to a support suitable for electrophotographic use and removing small areas from the layer.
2. Description of the Prior Art
Examples of screened photoconductive elements are disclosed in IBM Technical Disclosure Bulletin, Vol. 18, No. 10, March 1976 at pp. 3164-65 and Xerox Disclosure Journal, Vol. 5, No. 2, March-April 1980 at p. 131. The Xerox disclosure mentions forming an insulating dot pattern by overcoating with a blocking layer. The IBM disclosure mentions the evaporation of the charge generation material through a pattern mask. Neither mentions forming the screened pattern by the removal of material.
U.S. Pat. No. 2,777,256 relates to a method of cleaning and roughening a metallic support surface in preparation for the application of a coating layer by blasting with a spray of fine abrasive particles. The entire metallic support surface is blasted according to U.S. Pat. No. 2,777,256 with a large portion of the surface being removed. French Pat. No. 2,522,992 discloses a blasting method for roughening a metallic surface similar to the method described in U.S. Pat. No. 2,777,256.
European Patent Application 0,025,253 relates to an optical recording disk in which holes are made in a recording layer by means of a laser. The substrate under the recording material has been roughened or scratched chemically or mechanically so that the recording layer exhibits the same discontinuities. It is a very time consuming process to generate a large number of holes in the recording material in this manner.
Netherlands Patent Application 8,400,922, which is not a prior publication, discloses a method for producing a screened layer for an electrophotographic element by applying a homogeneous layer to a support. Small areas are then removed from a charge-generating layer applied to the support in accordance with a dot or line pattern by means of a laser. An excellent screened layer can be produced by using this method. The disadvantage of this method, however, is that it is fairly time consuming if part of the layer, for example 25%, is to be removed on a large scale in the form of small areas of a size, for example, of about 25 .mu.m. Thus, there is a need for a method of quickly removing on a large scale, small areas of a layer for an electrophotographic element to produce a screened layer.